Fluid Leak Diagnosis

Systematic diagnosis of fluid leaks on the 2023 Rivian EDV 500, including inspection of EV-specific cooling systems, brake fluid, differential gear oil, and washer fluid systems.

Warnings

Tools required

Parts

• Replacement seals or gaskets × 1 — Determined after diagnosis

Fluids

• EV Transmission Fluid
• EV Battery/Motor Coolant
• DOT 4 Brake Fluid
• 75W-90 GL-5 Gear Oil
• Transfer Case Fluid
• Windshield Washer Fluid

Preparation

1. Park vehicle on level surface and engage parking brake
2. Ensure vehicle has been stationary for at least 2 hours to allow fluids to settle and systems to cool
3. Place wheel chocks behind rear wheels
4. Document any customer complaints about leak location, fluid color, or odor
5. Check Rivian service bulletins for known leak issues on 2023 EDV 500 models
6. Photograph undercarriage before cleaning to document existing conditions

Procedure

1. 1

   Initial Visual Inspection - Exterior
   Walk around vehicle and inspect ground beneath for fluid stains or puddles. Note color, consistency, and location. Clear fluids may be washer fluid or water condensation. Orange/pink fluids indicate EV coolant. Brown/amber indicates gear oil. Clear/amber with slippery feel indicates brake fluid. Document findings with photographs showing location relative to vehicle position.
2. 2

   Raise Vehicle and Secure
   Lift vehicle using approved lift points specified in Rivian service manual (located on chassis rails). Raise to comfortable working height. If using jack stands, position at reinforced jacking points. Ensure vehicle is stable before working underneath. Remove plastic underbody panels if installed to access drivetrain components.
3. 3

   Clean Undercarriage
   Using degreaser and pressure washer or steam cleaner, thoroughly clean undercarriage focusing on areas around battery pack, motor housings, differential housings, brake lines, coolant hoses, and transfer case. Remove all existing fluid residue, dirt, and road grime to establish clean baseline for leak detection. Allow to dry completely.
4. 4

   Inspect EV Cooling System
   Examine battery pack coolant lines, motor cooling lines, and all hose connections for wetness, staining, or active leaks. Check coolant reservoir level (located in front compartment) - low level indicates leak. Inspect coolant pump housing and connections. Look for orange/pink EV coolant residue on battery pack seams or cooling plate connections. Check expansion tank cap seal and overflow tube.
5. 5

   Inspect Front and Rear Drive Units
   Examine front and rear electric motor housings for EV transmission fluid leaks at drive unit seals, breather vents, and mounting points. Check axle shaft seals where halfshafts enter drive units. Look for reddish transmission fluid residue. Inspect drive unit fill and drain plugs for seepage. Check that breather tubes are not clogged or damaged.
6. 6

   Inspect Differential Systems
   Check front differential (1.5 qt capacity) and rear differential (2.0 qt capacity) for gear oil leaks. Inspect pinion seals, axle seals, cover gaskets, and fill/drain plugs. Look for amber/brown GL-5 gear oil residue. Check differential breather tubes for proper routing and signs of fluid expulsion. Verify differential housings are not cracked or damaged.
7. 7

   Inspect Transfer Case
   Examine transfer case housing (2.5 qt capacity) for fluid leaks at seals, gaskets, and mounting points. Check input and output shaft seals, fill and drain plugs, and case mating surfaces. Look for amber transfer case fluid residue. Inspect breather assembly for blockage or damage that could cause pressure buildup.
8. 8

   Inspect Brake System
   Check all brake lines, flexible hoses, and connections for DOT 4 brake fluid leaks. Inspect master cylinder reservoir for proper level - low level indicates leak. Examine brake calipers at all four corners for piston seal leaks or bleeder valve seepage. Check for fluid on inside of wheels. Inspect ABS modulator and brake booster connections for wetness. Brake fluid is clear to amber and feels slippery.
9. 9

   Inspect Washer Fluid System
   Check windshield washer fluid reservoir (3.5 qt capacity) for cracks or damage. Inspect pump connections and all washer fluid lines running to front and rear nozzles. Look for blue/green washer fluid stains. Test washer system operation and observe for external leaks at nozzles, line connections, or pump housing while system operates.
10. 10

    Apply UV Dye if Necessary
    If leak source is not visually apparent after cleaning, add UV dye to suspected fluid system following manufacturer instructions. For coolant leaks, add dye to coolant reservoir. For gear oil or transfer case leaks, add to respective fill ports. Drive vehicle 10-20 miles to circulate fluid. Return to lift and inspect with UV light to trace leak path.
11. 11

    Perform Dynamic Inspection
    With vehicle still raised, have assistant start vehicle and engage drive mode (do not lower vehicle with wheels spinning). Observe fluid systems under operating conditions. Check for leaks that only appear when system is pressurized. Monitor coolant pump operation and observe for leaks at pump connections. Turn steering wheel lock-to-lock to check for CV boot leaks or axle seal seepage under load.
12. 12

    Check for System Pressure Issues
    If coolant or fluid leaks are present, verify system pressure is not excessive due to blockages. Check coolant system pressure cap rating and condition. Inspect all breather tubes on differentials, transfer case, and drive units for blockages that could cause seal failure. Verify coolant expansion tank is functioning properly and not over-pressurizing system.
13. 13

    Document Findings
    Take detailed photographs of all leak locations with measurements or reference points. Document fluid type, leak severity (seepage vs active drip), and affected components. Note fluid levels in all reservoirs. Create written report including suspected root cause, required parts, estimated repair time, and recommended additional services. Record any diagnostic trouble codes from vehicle systems.

Reassembly

1. Reinstall any underbody panels or shields removed during inspection
2. Lower vehicle carefully from lift or jack stands
3. Clean any spilled fluids from shop floor
4. Reset tire pressure monitoring system if wheels were removed

Verification

• Verify leak source has been positively identified and documented
• Confirm all fluid reservoir levels are at proper fill marks
• Ensure no tools or equipment remain under vehicle
• Review diagnostic findings with customer and provide repair estimate
• If UV dye was used, inform customer it will remain in system and may be visible during future service
• Verify vehicle operates normally with no warning lights related to fluid systems

More procedures for this vehicle